fix: prevent agent debug from blocking chat

ai_knowledge_base_v2/apps/backend/tests/test_production_readiness.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 from datetime import date
 import asyncio
 import json
+import time
 
 import pytest
 import httpx
@@ -22,6 +23,7 @@ from app.services.chat_service import ChatService
 from app.services.secret_service import ENCRYPTED_PREFIX, MASKED_SECRET, SecretService
 from app.services.security_state_service import SecurityStateService
 from app.services.auth_service import AuthService
+from app.services.model_service import ModelClientService
 from app.core.observability import RequestObservabilityMiddleware
 
 
@@ -138,6 +140,26 @@ def test_request_id_is_returned_without_breaking_response():
     assert response.json() == {"ok": True}
 
 
+def test_agent_debug_model_call_does_not_block_event_loop(monkeypatch):
+    def blocking_debug(*_args, **_kwargs):
+        time.sleep(0.15)
+        return {"ok": True}
+
+    monkeypatch.setattr(ModelClientService, "debug_model", blocking_debug)
+
+    async def verify_concurrency():
+        started = time.perf_counter()
+        task = asyncio.create_task(ModelClientService.debug_model_async(object(), object(), {}))
+        await asyncio.sleep(0.02)
+        event_loop_delay = time.perf_counter() - started
+        result = await task
+        return event_loop_delay, result
+
+    delay, result = asyncio.run(verify_concurrency())
+    assert delay < 0.10
+    assert result == {"ok": True}
+
+
 def test_readiness_reports_dependency_state(monkeypatch):
     from app.api import health